Injection device

ABSTRACT

An injection device has a housing ( 50, 60 ) and therein a spring for storing energy for an injection operation. The spring ( 94 ) impinges, in the proximal direction, upon an ejection member ( 92 ) for ejecting injection liquid ( 16 ) from a vessel, displaceably arranged in the housing, at whose proximal end an injection needle is attached. Located in the housing is a displacement member ( 36 ), displaceable in the longitudinal direction, for displacing the vessel ( 14 ) in the proximal direction, in order to effect a movement of the injection needle ( 18 ) in the proximal direction and, thus, its insertion. Provided on the ejection member ( 92 ) is a detent lug ( 100 ), associated with which is a corresponding detent opening ( 102 ) in the displacement member ( 36 ). A control member ( 70 ), effective in travel-dependent fashion, serves to disengage the detent lug ( 100 ) from the detent opening ( 102 ) when the displacement member ( 36 ), during the injection operation, has traveled a predefined distance in the proximal direction.

FIELD OF THE INVENTION

The invention concerns an injection device having a housing and havingan energy storage spring for storing energy for an injection operation.This energy serves preferably for automatically inserting an injectionneedle, and optionally also for automatic injection of an injectionliquid. The preferred field of application of the invention is aninjection device for one-time use, often also referred to as adisposable syringe.

SUMMARY OF THE INVENTION

It is the object of the invention to make a new injection deviceavailable.

According to the invention, this object is achieved by having a controlmember which disengages a detent lug once a displacement member hastraveled a predefined distance in the proximal direction. What isthereby obtained, in simple fashion, is sequential execution of theinjection operation, i.e. first the injection needle (hollow needle) isinserted into the patient, and only then, when the needle is already inthe subcutaneous fatty tissue, is the active ingredient present in theinjection device injected.

Another way of achieving the stated object is to use a spring-loadedneedle protection sleeve. Because the proximal and distal end positionsof the needle protection sleeve are a function of the position of thevessel container and thus of the displacement member, these endpositions can be optimally adapted to requirements before and after aninjection.

Further details and advantageous developments of the invention areevident from the exemplary embodiment described below and depicted inthe drawings, which is in no way to be understood as a limitation of theinvention.

BRIEF FIGURE DESCRIPTION

In the drawings:

FIG. 1 shows an injection device according to the present invention inlongitudinal section and in its cocked position, i.e. the positionbefore an injection, and at enlarged scale; in reality, the devicedepicted in FIG. 1 has, for example, a length of approximately 18 cm andhas approximately the shape of an oversized fountain pen;

FIG. 2 is a plan view of the point shown cut away in FIG. 1, view in thedirection of arrow II of FIG. 1;

FIG. 3 is a more greatly enlarged depiction of the upper half of theinjection device of FIG. 1 with the device in the cocked position, i.e.before an injection operation;

FIG. 4 is a view similar to FIG. 3 but after initiation of an injectionoperation, although the needle has merely been inserted whereas aninjection has not yet taken place;

FIG. 5 is a view similar to FIGS. 3 and 4, but after an injection hasbeen completely performed; and

FIGS. 6-8 are schematic depictions to explain the sequential executionof an injection;

FIG. 9 shows the proximal portion of the injector before removal of theneedle cover cap which covers the hollow needle in sterile fashion;

FIG. 10 is a perspective view for better comprehension of FIG. 9;

FIG. 11 is a perspective view of the proximal end segment of the needleprotection sleeve;

FIG. 12 is a view of the proximal portion of the injector upon removalof the needle cover cap;

FIG. 13 is a perspective view for better comprehension of FIG. 12;

FIG. 14 is a view of the proximal portion of the injector after theneedle has been inserted into the subcutaneous fatty tissue of thepatient;

FIG. 15 is a view of the proximal portion of the injector after theneedle has been pulled out; the latter is, in this context, completelysurrounded by the needle protection sleeve to prevent anyone from beinginjured by the needle or infected with a disease;

FIG. 16 is a plan view of an arrangement of barbs provided on the needleprotection sleeve;

FIG. 17 is a longitudinal section viewed along line XVII—XVII of FIG.16;

FIG. 18 is a schematic view of the barb arrangement before becomingeffective; and

FIG. 19 is a schematic view of the barb arrangement after becomingeffective.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the description which follows, the terms “proximal” and “distal” areused in the manner usual in medicine, i.e. “proximal”=facing toward thepatient (the end of the injection device having injection needle 18),and “distal”=facing away from the patient.

FIG. 1 shows the totality of an injection device 10 in longitudinalsection. In the exemplary embodiment, this is an injection device forone-time use, also called an autoinjector, but the invention can also beused in the context of injection devices that allow multiple use. Inthis embodiment, there is located in the interior of injection device 10an injection syringe 12 of commercially available design, having acylindrical portion 14 to receive the injection liquid 16, at whoseproximal end an injection needle 18 is attached in the usual fashion.

Cylindrical portion 14 has at the top, in the usual fashion, anenlargement 20 in the form of so-called syringe flanges. Also providedis a piston 22 that is connected to a piston rod 24 that has a pressureplate 26 at its distal end. When pressure is exerted on pressure plate26 in the direction of arrow 28, liquid 16 is then ejected throughneedle 18, as is familiar to those skilled in the art.

Cylindrical portion 14 of commercially available syringe 12 is locatedin the cylindrical recess 29 of a vessel container 30, which can also bereferred to as the syringe container and which has at its distal endregion a shoulder 32 against whose distal side enlargement 20 rests asdepicted. Shoulder 32 transitions into a collar-shaped segment 34 that,as depicted, is firmly connected to a displacement member 36, ofsubstantially cylindrical configuration, which with its proximal end 38grips syringe flanges 20 so that the latter are firmly connected todisplacement member 36 and vessel container 30, and syringe 12constrainedly follows their movements.

Vessel container 30 has in the proximal end region two grooves orrecesses 40, 40′ which lie diametrically opposite one another. A needleprotection sleeve 46 has two resilient segments 42, 44, each with aradially inwardly protruding projection 42′, 44′ at its free end.Projection 42′ protrudes into groove 40, projection 44′ into groove 40′.FIG. 2 shows resilient segment 42 in plan view.

Needle protection sleeve 46 is thus displaceable between a proximal anda distal end position, whose spacing is determined by the (identicallength of grooves 40, 40′. As vessel container 30 is displaced in theproximal direction upon injection, the position of grooves 40, 40′ alsochanges, and thus so do the proximal and distal end positions of needleprotection sleeve 46 as will be described in detail below, i.e. both endpositions are then displaced in the proximal direction. Grooves 40, 40′also effect longitudinal guidance of needle protection sleeve 46.

Needle protection sleeve 46 is slidingly displaceable in cylindricalinner side 52 of a proximal housing portion 50. From cylindrical innerside 52, an annular shoulder 54 protrudes radially inward. This servesan abutment for a compression spring 56 which, as depicted, acts uponneedle protection sleeve 46 in the proximal direction, i.e. toward thepatient.

Collar-shaped segment 34 is also displaceable in cylindrical inner side52 as depicted, specifically from its distal end position depicted inFIGS. 1 and 3 to its proximal end position depicted in FIGS. 4 and 5, inwhich segment 34 is in contact against annular shoulder 54.

Firmly connected to proximal housing portion 50, as depicted, is adistal housing portion 60. The latter has an interior space 62 that isclosed off at the top, i.e. at the distal end, by a closure wall 64.Located on the outer side of housing portion 60, in an annular groove66, is a rotatable annular element 68 that has a control member or camsegment 70 which projects through an opening 72, as depicted, into theinterior of distal housing portion 60.

Located on the outer side of distal housing portion 60, as depicted, isa triggering member 74 that has approximately the shape of the retainingclip of a fountain pen. In the region of its unattached (proximal) end,triggering member 74 has a radially inwardly protruding projection 76which serves to trigger an injection operation. In FIG. 1, this isprevented by annular element 68, which is in its locking position andthus blocks any movement of projection 76 to the left. FIGS. 3 through 5show this annular element 68 in a rotational position in which it makespossible the triggering of an injection, because there is presenttherein, opposite projection 76, a recess 80 of annular element 68 whichthen aligns with a recess 82 of distal housing portion 60.

As FIG. 1 shows, in the cocked state a radially outwardly deflectingdetent element 84, which in this case is configured integrally withdisplacement member 36, snaps into recess 82. Associated with thisdetent element 84 on the inner side of distal housing portion 60 is alongitudinal groove 86 in which detent element 84 is displaced duringthe injection operation (cf. FIGS. 4 and 5).

An ejection member 92 is arranged in slidingly displaceable fashion incylindrical inner side 90 of displacement member 36. It is acted upon inthe proximal direction by a compression spring 94 that, in the cockedstate (FIGS. 1 and 3), stores the energy necessary for performing aninjection operation. As depicted, spring 94 is braced at its distal endagainst housing segment 64, and at its proximal end against an annularshoulder 96 of ejection member 92.

Ejection member 92 is configured integrally with a flexible detentmember or lug 100 whose form and function are best evident from FIGS. 6through 8. When injection device 10 is in the cocked state (FIGS. 1 and3), detent member 100 projects into a detent opening or recess 102 ofdisplacement member 36, and through this recess 102 it projects with aradial protrusion 103 radially outward into a radial space or gap 104between displacement member 36 and inner side 106 (FIGS. 6 and 7) ofdistal housing portion 60. In that context, it is braced at a radiallyextending surface 108 against a corresponding countersurface of openingor recess 102, as shown in greatly magnified fashion in FIG. 6, so thatthe force of spring 94 is transferred via detent member or lug 100 todisplacement member 36, and acts upon the latter in the proximaldirection before an injection begins.

Mode of operation

In order to trigger an injection, in FIG. 3 member 74 is acted upon by aforce F and thereby displaces resilient detent member 84 of displacementmember 36 radially inward, so that the latter comes out of engagementwith recess 82 of distal housing portion 60.

As a result, as shown in FIG. 4, ejection member 92 and displacementmember 36 can be displaced together in the proximal direction inresponse to cocked spring 94, since they are coupled to one another byflexible detent member or lug 100, and needle 18 is thus displaced intothe position labeled 18′ in FIG. 1, thus inserting it into thesubcutaneous fatty tissue of the patient (cf. FIG. 14).

As shown in FIG. 4, in this context an axial gap 110 initially remainsbetween proximal end 112 of ejection member 92 and pressure plate 26,since the syringe 12 moves synchronously with displacement member 36 andconsequently the positions of these parts relative to one another do notchange. The size of gap 110 depends on the magnitude of liquid volume 16in syringe 12.

When the position shown in FIG. 4 is reached, flexible detent member 100is deflected radially inward by projection 70 so that it comes out ofengagement with recess 102 of displacement member 36.

The manner in which this occurs is shown by FIGS. 6 through 8, whichactually require no explanation. Projection 70 has on its distal side anoblique surface that, on radial protrusion 103, corresponds to acomplementary oblique surface 114 of flexible detent member or lug 100.When a movement occurs in the direction of arrow 28, oblique surfaces112 and 114 slide along one another and push flexible detent member 100radially inward in the direction of an arrow 116, so that (as shown inFIG. 7) it comes out of engagement with the associated recess 102 ofdisplacement member 36 and (as shown in FIG. 8) moves automatically inthe proximal direction in response to compression spring 94.

In this context, as shown in FIG. 5, proximal end face 112 of ejectionmember 92 presses against pressure plate 26 and displaces the latter asfar as the stop in the commercially available syringe 12, so that theliquid 16 is ejected from the latter and injected through needle 18 intothe patient. FIG. 5 shows the position that is reached after completionof the (automatically proceeding) injection operation.

FIG. 9 is largely the same as the depiction of FIG. 1. It shows themanner in which, prior to an injection, a sterile needle cover cap 120must be pulled off in the direction of an arrow 122 so that the needlecan be inserted. In the present case, removal of needle cover cap 120would be possible only with the aid of a forceps.

For this reason, needle protection sleeve 46 has two radial projections124, 126 with which it projects into axially extending cutouts 128, 130of proximal housing portion 50 and is axially displaceable in thosecutouts.

FIG. 11 shows, in a perspective depiction, the proximal portion ofneedle protection sleeve 46. This also has a detent arrangement 132having two resilient barbs 134, 136 that are located in a window 138.Arrangement 132 and its function are explained below. As clearlydepicted in FIG. 17, barbs 134, 136 project inward and outward radiallybeyond inner circumference 46′ and outer circumference 46′′,respectively, of needle protection sleeve 46. The outward protrusionprovides guidance in a longitudinal groove 154 of housing portion 50, asdepicted in FIGS. 18 and 19. The purpose of the inward protrusion is todeflect barbs 134, 136 toward one another upon assembly (cf. FIG. 18).

FIGS. 12 and 13 show the manner in which needle protection sleeve 46 hasbeen displaced distally in the direction of an arrow 140 relative tohousing 50, so that the patient can now grasp the sterile needle covercap 120 through recesses 128, 130 and pull it off needle 18 in thedirection of arrows 122 in order to prepare for an injection.

FIG. 14 shows needle 18 after it has been inserted into subcutaneousfatty tissue 150 of the patient. This position corresponds to theposition depicted in FIG. 4 (before injection of the liquid), and isidentical to the position depicted in FIG. 5 (after injection of theliquid). The difference between the two figures is the position ofpiston 22 in cylinder 14; this piston is not depicted in FIG. 14.

In FIG. 14, needle protection sleeve 46 once again occupies the positiondepicted in FIGS. 9 and 10, but its two projections 42′, 44′ are nowlocated at the upper (i.e. distal) end of grooves 40 and 40′, sincevessel container 30 has been displaced in the proximal direction uponthe insertion of needle 18.

As a result, the distal end position of needle protection sleeve 46 hasthus correspondingly changed, as has its proximal end position, whichhas migrated farther down as compared to FIG. 14.

When needle 18 is then pulled out of the subcutaneous fatty tissue asshown in FIG. 15, needle protection sleeve 46 is thus displaced by itscompression spring 56 into its new proximal end position, which isdepicted in FIG. 15 and in which it completely encloses needle 18 inorder to prevent any danger of injury.

In the position shown in FIG. 15, needle protection sleeve 46 ispermanently snap-locked in place so that it cannot inadvertently be slidback against the force of compression spring 56, the result of whichwould be that someone could be injured or infected by needle 18. This isaccomplished by way of the two detent hooks 134, 136 of apparatus 132,which is depicted in perspective in FIG. 11. Associated with thesedetent hooks in housing portion 50 on its inner side is a longitudinalgroove 154 which is narrow in its distal region 156 so that detent hooks134, 136 are compressed there, as depicted in FIG. 18.

As depicted in FIG. 19, when device 10 is in the position shown in FIG.15, detent hooks 134, 136 arrive in a wider region 158 at the proximalend of groove 154 and thus snap into place at transition point 160. Thiscorresponds to the position of the injector shown in FIG. 15, in whichneedle protection sleeve 46 is permanently snap-locked into its newproximal end position which has thus also become the (final) distal endposition when the injection device, after use, has become waste.

With the exception of springs 56 and 94, the parts of injection device10 are preferably made of plastic, for example of ABS(acrylonitrile-butadiene-styrene polymer), PC (polycarbonate), or POM(polyoxymethylene).

Preferred materials are:

Housing portions 50, 60, needle protection housing 46, ejection member92, and displacement member 36: POM or ABS; Vessel container 30: POM orPC.

The selection of plastics is preferably consistent in order to simplifyrecycling of the injection device.

Many variations and modifications are of course possible in the contextof the present invention.

What is claimed is:
 1. An injection device comprising a housing and anenergy storage spring arranged therein for storing energy for aninjection operation, said housing having an end proximal to a patientand an end distal with respect to said patient, an ejection member,acted upon in the proximal direction by said energy storage spring, forejecting injection liquid from a vessel with injection liquid,displaceably arranged in the housing, said vessel having a proximal endadapted for mounting an injection needle; a displacement member,displaceable in the longitudinal direction in the housing, fordisplacing the vessel in the housing in the proximal direction in orderto effect a movement of the injection needle in the proximal directionand thus, during the injection operation, an insertion of the injectionneedle; a detent lug, provided on the ejection member, associated withwhich is a corresponding detent opening in the displacement member, thedetent lug and detent opening together forming a releasable joiningmember between the ejection member and displacement member; and acontrol member, effective in position-dependent fashion, for disengagingthe detent lug from the detent opening when the displacement member,during the injection operation, has traveled a predefined distance inthe proximal direction, in order, after disengagement of the detent lug,to effect a proximal movement of the ejection member independent of aproximal movement of the displacement member, and thus an ejection ofinjection liquid from the vessel.
 2. The injection device as defined inclaim 1, wherein the detent lug, in the snapped-in state, projects witha radial protrusion beyond the outer circumference of the displacementmember, and by way of an element located in the displacement path ofsaid radial protrusion, is deflectable inward when a proximal movementof the displacement member occurs and thereby is releasable from thedetent opening associated with it.
 3. The injection device as defined inclaim 2, in which the detent lug has on its proximal side, viewed frominside to outside, firstly a substantially radially extending segmentfor snap-locking with the detent opening associated with it, andadjacent thereto an obliquely extending segment that, proceeding fromthe radially extending segment, extends obliquely outward in a radialand distal direction.
 4. The injection device as defined in claim 1, inwhich there is provided, between the displacement member and thehousing, a releasable first detent connection which, when the energystorage spring is cocked, allows snap-locking of the displacement memberin the housing, and which, when released, effects triggering of aninjection operation.
 5. The injection device as defined in claim 4, inwhich a locking member for locking the first detent connection isprovided in order to make triggering of an injection lockable.
 6. Theinjection device as defined in claim 1, in which the ejection member isarranged in the interior of the displacement member is arranged in theinterior of the displacement member and is displaceable relative to thelatter in the longitudinal direction of the injection device.
 7. Aninjection device having a housing and a spring arranged therein servingas energy store for the insertion of an injection needle, having aspring acting in the proximal direction on said displacement member, thedisplacement member being displaceable in the housing between a distaland a proximal end position, and there being associated with it areleasable detent apparatus in order to snap-lock it in its distal endposition in which the spring is cocked; having a vessel container forreceiving a vessel having injection liquid, said vessel container being,at its proximal end, connectable to the injection needle, and beingjoined to the displacement member in such a way that movements of thedisplacement member in the proximal and in the distal direction aretransferred to the vessel container; and having a needle protectionsleeve, arranged in the region of the injection needle at the proximalend of the housing, which sleeve is displaceable from a proximal endposition, against the force of an associated spring, into a distal endposition, the proximal and distal end positions of the needle protectionsleeve being a function of the position of the vessel container relativeto the housing.
 8. The injection device as defined in claim 7, in whichthe proximal end position of the needle protection sleeve before aninjection operation is substantially identical to the distal endposition of the needle protection sleeve after an injection operation.9. The injection device as defined in claim 7, in which there isprovided, between the needle protection sleeve and vessel container, amechanical connection which makes possible a displacement of the needleprotection sleeve relative to the vessel container within predefinedlimits.
 10. The injection device as defined in claim 7, in which theneedle protection sleeve has a detent arrangement which, in the regionof a proximal end position of the needle protection sleeve broughtabout, after completion of an injection operation, by the springassociated with the needle protection sleeve, effects a snap-lock joinwith the housing.
 11. An injection device comprising a housing and anenergy storage spring arranged therein for storing energy for aninjection operation, an ejection member, acted upon in the proximaldirection by said spring, for ejecting injection liquid from a vesselwith injection liquid, displaceably arranged in the housing, said vesselhaving a proximal end adapted for mounting an injection needle; adisplacement member, displaceable in the longitudinal direction in thehousing and joined to the ejection member via a releasable joiningmember which is firmly connected to the vessel for the injection liquid,for displacing the vessel in the housing in the proximal direction inorder to effect a movement of the injection needle in the proximaldirection and thus, during the injection operation, an insertion of theinjection needle; a control member, effective in position-dependentfashion, for releasing the releasable joining member when thedisplacement member, during the injection operation, has traveled apredefined distance in the proximal direction; and a releasable detentconnection, which is provided between the displacement member and thehousing, allows snap-locking of the displacement member in the housingwhen the energy storage spring is cocked, and is triggerable by radialpressure on an actuation member, in order, by way of radial pressure onsaid actuation member, to make possible the triggering of an injectionoperation in which first the displacement member and ejection member aretogether driven by the energy storage spring via the joining member inorder to effect insertion of the injection needle, and then, after thereleasable joining member has been released, injection liquid is ejectedfrom the vessel by the ejection member in response to the energy storagespring.
 12. The injection device as defined in claim 11, in which alocking member for locking the releasable detent connection is provided.13. The injection device as defined in claim 12, in which the lockingmember is configured to lock a triggering movement of the actuationmember.
 14. The injection device as defined in claim 12, in which thelocking member has a portion that is configured as a position-dependentcontrol member for releasing the releasable joining member.
 15. Theinjection device as defined in claim 13, in which the locking member hasa portion that is configured as a position-dependent control member forreleasing the releasable joining member.